1. Field of the Invention
This invention relates to toothbrushes and more particularly toothbrushes utilizing sonic and ultrasonic acoustic mechanism to increase the effectiveness of the toothbrushes and to provide for enhanced oral hygiene.
2. Description of Prior Art
Some of the early art of powered toothbrushes attempted to increase the speed of bristle vibrations by various sonic frequency and ultrasonic frequency means. These devices are exemplified by U.S. Pat. No. 3,335,443 by Parisi, U.S. Pat. No. 3,809,977 by Balamuth, and U.S. Pat. No. 4,192,035 by Kuris. These proposals did not utilize ultrasonic pressure waves to impact upon the plaque and periodontal bacteria on the teeth and gums; they were merely faster vibrating mechanical toothbrush designs. It is not known if any of these patents were utilized in commercially available toothbrushes.
The first commercially available ultrasonic toothbrush utilizing ultrasonic pressure waves to help remove plaque and destroy periodontal bacteria was based on U.S. Pat. No. 5,138,733 by Bock, which contained a piezoelectric transducer in the tip of the brush head to generate the ultrasonic pressure waves, which were transmitted through the bristles to teeth and gums. While this was a great leap forward in toothbrush design, it was not optimal since a significant portion of the ultrasound energy generated by the piezoelectric transducer were lost due to various structural ultrasound attenuation mechanisms. Material interfaces are not 100% efficient. Each material interface that the ultrasound wave has to travel through, such as the adhesive to transducer interface and the adhesive to housing interface securing the transducer in the housing, the housing to the brush head interface, and the brush head to the bristle interface are reflecting some of the ultrasound energy back toward the transducer. In addition, the long aspect ratio thin bristles attenuated some of the ultrasonic energy generated by the piezoelectric transducer. In both U.S. Pat. Nos. 5,138,733 and 5,369,831 also by Bock, the transmission of ultrasound toward the back of the brush head was also greatly reduced due to the numerous surface interfaces and thick housing materials, which attenuated the ultrasound energy toward the back side of the brush head. Nevertheless, U.S. Pat. Nos. 5,138,733 and 5,369,831 still represented the best solution for ultrasonic toothbrushes at their time.
U.S. Pat. No. 7,269,873 B2 by Brewer et. al, entitled “Ultrasonic toothbrushes employing an acoustic waveguide” represents the next technological improvement in the art. The Brewer patent is essentially a modification of U.S. Pat. No. 5,138,733 by Bock, wherein Brewer provides an improvement in the efficiency of the transmission of the ultrasonic pressure waves from the transducer through the toothpaste and the fluids in the mouth to the teeth and gums by the addition of a waveguide, which is more efficient in transmission of the ultrasonic waves toward teeth and gums than the bristles in U.S. Pat. No. 5,138,733 by Bock. However, the waveguide suggested by Brewer while more efficient than the bristles in Bock's disclosure and practice, still attenuates the ultrasonic energy produced by the transducer, both by the waveguide to transducer interfaces and the waveguide itself. In an attempt to maximize the ultrasonic energy output from the acoustic waveguide toward teeth and gums Brewer utilizes an ultrasound-reflecting element (see FIG.1 item 28) or an alternative air-gap (see FIG. 4) on the back of the ultrasound transducer. Air-gaps are known in the art to reflect and stop propagation of ultrasound pressure waves. Both the ultrasound reflecting element and the air-gap are isolating ultrasound wave emission from the back of the brush-head and from the lips and cheeks.
U.S. Pat. No. 7,849,548 B2 by Bock represents the next technological improvement in ultrasonic toothbrushes. In his disclosure Bock eliminates all structural attenuation of ultrasound energy emitted by the piezoelectric transducer toward teeth and gums by bringing the transducer out of the brush head and getting it in direct contact with the toothpaste and the fluids between the toothbrush and the teeth and the gums, greatly enhancing the efficiency and efficacy of the design. There are no surface interfaces or any other material to attenuate ultrasound energy between the transducer and the fluids of the oral cavity on the side of the bristles and teeth and gums. However, similarly to Brewer, Bock also proposed an ultrasound reflecting closed cell foam (see FIG. 1 item 40) on the back of the ultrasound transducer, which isolates ultrasound emission from the back of the toothbrush and the lips and cheeks.
Both U.S. Pat. No. 7,269,873 B2 by Brewer et. al, and U.S. Pat. No. 7,849,548 B2 by Bock disclose the heretofore standard construction techniques of the ultrasound transducer art throughout history, wherein the objective always has been to maximize ultrasound emission from the single “working” side of the transducer by the application of ultrasound reflecting materials and ultrasound reflecting air-gaps on the non-working “back” side of the transducer. This ultrasound emission maximization from the single working side significantly reduced and most often completely eliminated ultrasound emission from the non-working back side of the transducers.
The only known ultrasonic toothbrush in the prior art having an exposed ultrasound transducer is the U.S. Pat. No. 7,849,548 B2 by Bock. All other ultrasonic toothbrushes of the prior art, which are utilizing ultrasound transducers (see FIG. 1 of U.S. Pat. No. 5,138,733 by Bock, and FIG. 2 of US20130115571 A1 by Emecki) taught deploying the transducers inside of the plastic brush heads so they could not possibly come into contact with the user's teeth. It was discovered during the implementation of U.S. Pat. No. 7,849,548 B2 by Bock that the piezoelectric transducer exposed between the bristle tufts (see FIG. 7) does come into contact with the teeth when used by significant force in certain brushing sequences. Contacting the teeth, the vibrating piezoelectric transducer creates an uncomfortable sensation for the user, limiting utility of the device.
U.S. Patent Application US 20130115571 A1 by Emecki discloses a device wherein the toothbrush bristles are directly attached to one side of the transducer to act as waveguides and transfer the mechanical oscillation energy to the teeth. While Emecki does not describe the construction details of the brush head, it is clear from FIG. 2 of the disclosure that the mechanical oscillations are limited or completely eliminated by an air-gap or reflecting material on the back side of the transducer. Emecki's entire teaching and effort is focused on maximizing emission of mechanical oscillations into the bristles.
While progress to date was significant, the fact remains that the ultrasound toothbrush art has been focused on and only been successful to date to effectively remove plaque and periodontal bacteria from the teeth and gum surfaces.
Some people are suffering from various oral diseases, such as Recurrent Aphthous Stomatitis (RAS), commonly referred to as canker sores, Lichen Planus (LP) a chronic inflammatory disease with painful erosive or ulcerative areas mostly in the cheeks opposite to the teeth, and Mucositis (painful ulcerative lesions) caused by Anticancer Chemotherapy, which are appearing on the buccal and labial mucosa, the inside surfaces of the cheeks and the lips.
The ulcerative lesions of Mucositis are colonized by opportunistic bacterial micro organism, which create secondary infections making the already difficult to handle Chemotherapy process even less tolerable. There is evidence in the scientific community to support that RAS and LP are an aberrant immune response to the presence of oral flora. Thus a beneficial effect from the reduction in the oral bacterial load would be anticipated. Treatment with immunosuppressive agents, such as systemic or topical corticosteroids, will reduce RAS and LP activity in most patients with the disease. Unfortunately, this reduction is transient, and lesions quickly recur when treatment is discontinued. Because of the significant systemic side effects of corticosteroids, such as glaucoma, fluid retention, increased blood pressure, mood swings, osteoporosis, and more, the treatments with immunosuppressive corticosteroids cannot be tolerated for an extended period of time; the immunosuppressive corticosteroids treatments are only short-term temporary solutions. Therefore an effective therapeutic modality that is well tolerated for a long time would be of great value.
The ultrasonic toothbrush is a well-tolerated modality without any side effects. The limited amount of Ultrasound emitted from the backside of the first generation ultrasonic toothbrush based on U.S. Pat. No. 5,138,733 has been demonstrated by clinical studies to have a modest beneficial effect (46% reduction in the duration of RAS lesions as well as of decreasing the number of lesions that develop) on recurrent aphthous stomatitis. This modestly beneficial effect of the first generation ultrasonic toothbrush was limited by the structural attenuation of the ultrasonic pressure waves escaping through the backside of the brush head, contacting the inside surfaces of the lips and cheeks.
So, even the latest state of the art ultrasonic toothbrushes are not optimally efficient to attack and destroy the various oral bacteria residing and colonizing on the inside of the lips and cheeks opposite to teeth and gums, which are causative of RAS and LP.
The art is still missing the opportunity to conveniently and concurrently with removing plaque and periodontal bacteria from teeth and gums, also to provide relief of RAS and LP and improve the health status of people suffering from RAS and LP.
In summary, RAS and LP are both an aberrant immune responses related to oral flora, still waiting for an effective relief, by a well-tolerated modality, without immunosuppressive agents and their systemic side effects.
The ultrasonic toothbrush being a well-tolerated modality is a good candidate, but the quest for a multi purpose spatially highly effective device is still not fulfilled.